Conventionally, as an inkjet head, there is known a head of a type in which a nozzle plate having a plurality of nozzle orifices is provided with a plurality of piezoelectric elements. Each piezoelectric element displaces a portion of the nozzle plate around the corresponding nozzle orifice in the thickness direction to change the pressure of the ink pressure chamber communicating with the nozzle orifice. This pressure change discharges ink from the nozzle orifice.
As the nozzle plate is thinned to enable each piezoelectric element to displace the nozzle plate, the length of the nozzle orifice decreases. Shortening the nozzle orifice will present a possibility that the movement of the ink meniscus may generate air bubbles in the nozzle orifice to result in unstable discharge of an ink droplet.
For this reason, there has been developed a head including nozzle extension portions for extending the nozzle length on the ink pressure chamber side of a nozzle plate (see, for example, Japanese Patent Laid-Open No. 2013-67026).
It is, however, difficult to position the nozzle extension portions with respect to the nozzle orifices. This makes it difficult to manufacture a head. In addition, such nozzle extension portions are provided separately from a nozzle plate, and hence have low mechanical strength.
Therefore, there have been demands for the development of an easily-manufactured, low-profile inkjet head having high mechanical strength.